Dark Angel

S7, E2: The body of a young man is discovered face-down in a river by Thrunton Woods, bludgeoned to death. But with no ID on the body, tracing the victim's identity proves difficult for DCI Vera Stanhope and her team. Vera is forced to make headway with the only clues they have, a mourning ring worn around the young man's neck, needle marks on the body, and a drugs wrap with a distinctive stamp - 'Dark Angel'. Tracing the stamp draws Vera to Gateshead and into Newcastle's criminal underbelly, where it transpires the victim, Nathan, had several ties with people both dangerous and vulnerable; people with good reason to want Nathan out of the picture.